EP3710493B1

EP3710493B1 - Article comprising a core-shell graft copolymers with improved surface properties

Info

Publication number: EP3710493B1
Application number: EP18800970.8A
Authority: EP
Inventors: Dejin Li; Vern Lowry
Original assignee: SABIC Global Technologies BV
Current assignee: SABIC Global Technologies BV
Priority date: 2017-11-16
Filing date: 2018-11-16
Publication date: 2024-04-24
Anticipated expiration: 2038-11-16
Also published as: CN111201249A; WO2019096979A1; KR20200079332A; US11674033B2; CN111201249B; EP4169954A1; US20230257575A1; JP2021503521A; US20200270445A1; EP3710493A1; JP2023029424A

Description

The present invention relates to core-shell graft copolymers having improved surface properties. In particular, the invention relates to core-shell graft copolymers having improved surface properties when coated with a metallic coating. The invention further relates to a process for producing such core-shell graft copolymers. The invention also related to articles comprising a surface area of such core-shell graft copolymer, in particular to articles comprising a surface area of such core-shell graft copolymer where the surface is coated with a metallic coating.
The external surface structure is considered an important characteristic for many different articles. Where articles or parts of articles are manufactured from polymeric materials, is tends to be particularly desired that the surfaces of such articles that are made up of those polymeric materials demonstrate a very low quantity of surface defects. This is certainly the case in the situation where such surface is covered with a metallic coating. In many articles, including for example household appliances and vehicle interior parts, the use of parts made from polymeric materials to which a metallic coating is applied is widespread. Such parts demonstrate the appearance of a metallic part, but still are for the main part produced from polymeric materials, and thus provide all the advantages of such polymeric materials, including for example weight reduction, the ability to produce wide varieties of complex shapes, and reduced cost of production.
One group of polymeric materials that are commonly used in articles with a metallic coating are core-shell graft copolymers. A particular example of suitable core-shell graft copolymers are copolymers comprising elastomeric cores structures to which a thermoplastic polymer is graft copolymerised. Such copolymers have good impact strength properties and good elastic modulus properties, whilst still having hardness properties such to allow the use in articles where a particular surface scratch resistance is required. As quality requirements continue to increase, there continues to be a need to have access to polymeric materials that, when shaped into a moulded part and provided with a metallic coating, demonstrate a uniform surface with as little as surface defects as possible.
WO 2012/080407 is directed to a thermoplastic polymer especially suitable for metal plating resulting in metal plated finished articles having improved resistance against repeated impacts, while maintaining sufficient thermal stability, surface quality, superior adhesion between the substrate and the metal layer irrespective of the complexity of the design of the molded article and the kind of metal plating technique (e.g. conventional, electroless, physical vapour deposition, direct metal plating). The thermoplastic moulding composition is produced from a graft copolymer (A) a thermoplastic polymer that has a moisture content of 0 to 27 % by weight after work-up (B). Preferably, the composition additionally includes a thermoplastic polymer (C) that is not, or only to a limited amount, miscible with the thermoplastic polymer (B).
JP 2006291051 is directed to a thermoplastic resin composition. The thermoplastic resin composition comprises (B) a rubbery graft copolymer obtained by graft copolymerization of a vinyl monomer to a rubber in the presence of (A) a fatty acid-based surfactant wherein the counterion is sodium ion and coagulated with a calcium salt and (C) a polyacetal resin.
WO 2006/127223 is directed to a molding composition comprising an acrylic-styrene-acrylonitrile (ASA) resin comprising a discontinuous elastomeric phase dispersed in a rigid thermoplastic phase, wherein at least a portion of the rigid thermoplastic phase is grafted to the elastomeric phase; and wherein the thermoplastic phase comprises structural units derived from at least one vinyl aromatic monomer, at least one monoethylenically unsaturated nitrile monomers, and optionally at least one (C1-C12)alkyl- and aryl-(meth)acrylate monomer; and wherein the elastomeric phase is derived from a rubber substrate comprising structural units derived from at least one (C1-C12)alkyl(meth)acrylate monomer and at least one crosslinking agent comprising a polyethylenically unsaturated monomer; and wherein the rubber substrate comprises less than 5.6 micromoles of unreacted crosslinking agent per gram of rubber substrate based on the dry weight of the rubber substrate before grafting.
EP 2465883 is directed to an impact modifier in form of a core-shell copolymer impact modifier particle comprising a polymeric core and at least two polymeric layers, each layer with a different polymer composition, wherein at least one polymeric layer comprises a polymer that is a gradient polymer.
Further, improved requirements with regard to surface quality of articles made from polymeric materials continue to be requested also for applications besides articles with a metallic coating. The provision of materials allowing for production of articles with further reduced surface defects persists to be desired.
Disclosed herein is an article comprising a surface area comprising a core-shell graft copolymer, wherein the core-shell graft copolymer is a core-shell acrylonitrile-butadiene-styrene graft copolymer produced by coagulation of an aqueous latex comprising ≥ 10.0 wt% and <40 wt% of the copolymer and a quantity of a surfactant, wherein the coagulation involves the addition of a quantity of a multivalent metal salt, preferably a bivalent or trivalent metal salt, or a lithium salt, wherein the salt is a halogenide, wherein the surface area comprising the core-shell graft copolymer is coated with a metallic coating.
Such copolymer provides an improvement of the surface properties of moulded articles produced from such copolymers, as demonstrated by a reduction of the content of gels in the surface layer.
The core-shell graft copolymer may for example comprise elastomeric core particles and thermoplastic polymeric chains. In the core-shell copolymer, it is preferred that at least a fraction of the thermoplastic polymeric chains is covalently bound to the elastomeric core particles to form a graft copolymer. The core-shell graft copolymer may for example comprise a quantity of elastomeric core particles onto which a fraction of thermoplastic polymeric chains is covalently bound, and a quantity of thermoplastic polymeric chains that are not covalently bound to elastomeric core particles.
The core-shell graft copolymer may for example comprise greater than or equal to (≥) 10.0 weight percent (wt%) of elastomeric core particles with regard to the total weight of the core-shell graft copolymer, preferably ≥ 20.0 wt%, more preferably ≥ 30.0 wt%, even more preferably ≥ 40.0 wt%.
The core-shell graft copolymer may for example comprise less than or equal to (≤) 80.0 wt% of elastomeric core particles, preferably ≤ 70.0 wt%, more preferably ≤ 60.0 wt%, even more preferably ≤ 50.0 wt%.
The core-shell graft copolymer may for example comprise ≥ 10.0 wt% and ≤ 80.0 wt% of elastomeric core particles, preferably ≥ 20.0 wt% and ≤ 70.0 wt%, more preferably ≥ 30.0 wt% and ≤ 60.0 wt%, even more preferably ≥ 40.0 wt% and ≤ 60.0 wt%.
The elastomeric core particles may for example have an average particle size of ≥ 100 nanometers (nm), preferably ≥ 150 nm, more preferably ≥ 200 nm, even more preferably ≥ 250 nm. The elastomeric core particles may for example have an average particle size of ≤ 1,000 nm, preferably ≤ 500 nm, more preferably ≤ 400 nm. The elastomeric core particles may for example have an average particle size of ≥ 100 nm and ≤ 1000 nm, preferably ≥ 150 nm and ≤ 500 nm, more preferably ≥ 200 nm and ≤ 400 nm.
As disclosed herein, the average particle size is understood to be the D₅₀ particle size as determined in accordance with ISO 9276-2 (2014).
The elastomeric core particles are polybutadiene particles.
The core-shell graft copolymer may for example comprise ≥ 5.0 wt% of polymeric chains graft copolymerised onto the elastomeric core particles, with regard to the total weight of the core-shell graft copolymer, preferably ≥ 10.0 wt%, more preferably ≥ 15.0 wt%.
The core-shell graft copolymer may for example comprise ≤ 50.0 wt% of polymeric chains graft copolymerised onto the elastomeric core particles, with regard to the total weight of the core-shell graft copolymer, preferably ≤ 40.0 wt%, more preferably ≤ 30.0 wt%, even more preferably ≤ 20.0 wt%.
The core-shell graft copolymer may for example comprise ≥ 5.0 wt% and ≤ 50.0 wt% of polymeric chains graft copolymerised onto the elastomeric core particles, with regard to the total weight of the core-shell graft copolymer, preferably ≥ 5.0 wt% and ≤ 30 wt%, more preferably ≥ 10.0 wt% and ≤ 20.0 wt%.
The core-shell graft copolymer may for example comprise ≥ 20.0 wt% of polymeric chains that are not covalently bound the elastomeric core particles, with regard to the total weight of the core-shell graft copolymer, preferably ≥ 30.0 wt%, more preferably ≥ 40.0 wt%. The core-shell graft copolymer may for example comprise ≤ 75.0 wt% of polymeric chains that are not covalently bound to the elastomeric core particles, with regard to the total weight of the core-shell graft copolymer, preferably ≤ 65.0 wt%, more preferably ≤ 55.0 wt%. The core-shell graft copolymer may for example comprise ≥ 20.0 wt% and ≤ 75.0 wt% of polymeric chains that are not covalently bound to the elastomeric core particles, with regard to the total weight of the core-shell graft copolymer, preferably ≥ 30.0 wt% and ≤ 65.0 wt%, more preferably ≥ 40.0 wt% and ≤ 55.0 wt%.
The polymeric chains that are graft copolymerised onto the elastomeric core particles and the polymeric chains that are not covalently bound to the elastomeric core particles are derived from acrylonitrile and styrene. The polymeric chains may for example be produced using a reaction mixture comprising styrene and acrylonitrile wherein the molar ratio of styrene to acrylonitrile is in the range of 1.5 - 4.0.
The molar ratio of the elastomeric core particles to the total of the monomers may for example be in the range of 0.1 - 3.0, preferably in the range of 0.2 - 2.0. core-shell graft copolymer is produced using a reaction mixture comprising elastomeric core particles wherein the elastomeric core particles are polybutadiene particles, and a mixture of monomers comprising acrylonitrile and styrene.
The elastomeric core particles can be with at least two distinguishable peaks on particle size distribution, which is determined by a Beckman Coulter multi-wavelength laser diffraction particle size analyser type LS 13320 in accordance with ISO 13320. The first peak is at < 200 nanometers (nm). The second peak is at 200 - 500 nm. A possible third peak can be at > 800 nm with >0.1% volume percentage. Such particle size distribution elastomeric core particles can be produced by processing the monodistributed particles latex through high pressure mechanical homogenizer. Hence, the elastomeric core particles can be trimodal.
Optionally, the core-shell graft copolymer can be produced using a reaction mixture comprising elastomeric core particles wherein the elastomeric core particles are polybutadiene particles, and a mixture of monomers comprising acrylonitrile and styrene, wherein the molar ratio of styrene to acrylonitrile is in the range of 1.5 - 4.0, preferably 2.0 - 3.0, and the molar ratio of polybutadiene to the sum of styrene and acrylonitrile is in the range of 0.1 - 3.0, preferably 0.2 - 2.0.
The core-shell graft copolymer is an acrylonitrile-butadiene-styrene graft copolymer.
The core-shell graft copolymer may for example have an average particle size D₅₀ of ≥ 0.02 micrometer (µm), preferably ≥ 0.05 µm, more preferably ≥ 0.10 µm. The core-shell graft copolymer may for example have an average particle size D₅₀ of ≤ 3.00 µm, preferably ≤ 2.00 µm, more preferably ≤ 1.00 µm. The core-shell graft copolymer may for example have an average particle size D₅₀ of ≥ 0.02 µm and ≤ 3.00 µm, preferably ≥ 0.05 µm and ≤ 2.00 µm, more preferably ≥ 0.10 µm and ≤ 1.00 µm.
The aqueous latex comprises ≥ 10.0 wt% and <40 wt% particles of the core-shell graft copolymer with regard to the total weight of the aqueous latex, more preferably ≥ 20.0 wt% and ≤ 35.0 wt%, or ≥ 25.0 wt% and ≤ 35.0 wt%. For example, if the core-shell copolymer contains more than 40 wt% butadiene rubber, it may cause rubber agglomeration in the compounding step due to less surface coverage of SAN to the rubber core. This can result more defects in the final article surface after processing to make the metallic coating.
The aqueous latex comprising the core-shell graft copolymer can further comprise a quantity of a surfactant. For example, the aqueous latex may comprise 0.1 - 5.0 wt% of surfactant, with regard to the total weight of the aqueous latex, preferably 0.5 - 3.0 wt%.
The surfactant may for example be a fatty acid or a salt thereof, or a mixture of fatty acids or salts thereof. The fatty acid salt may be a potassium salt, a magnesium salt, a sodium salt, or a calcium salt. Preferably, the fatty acid salt is a potassium salt.
The fatty acid may be a single compound or a mixture of fatty acids. The fatty acid may be a saturated fatty acid, a monounsaturated fatty acid, a polyunsaturated fatty acid, or mixtures thereof. The fatty acid may for example be selected from dodecanoic acid, tetradecanoic acid, hexadecanoic acid, octadecanoic acid, eicosanoic acid, docosanoic acid, dodecenoic acid, tetradecenoic acid, hexadecenoic acid, octadecenoic acid, eicosenoic acid, docosenoic acid, dodecadienoic acid, tetradecadienoic acid, hexadecadienoic acid, octadecadienoic acid, eicosadienoic acid, docosadienoic acid, and mixtures of such compounds.
For example, the surfactant may be tallow fatty acid or tallow fatty acid potassium salt. Preferably, the surfactant is tallow fatty acid potassium salt.
The surfactant may for example be selected from fatty acids comprising ≥ 14 and ≤ 20 carbon atoms, preferably comprising ≤ 5 unsaturations, or mixtures thereof.
The core-shell graft copolymer disclosed herein can be produced by coagulation of an aqueous latex comprising a quantity of particles of the copolymer and a quantity of a surfactant, wherein the coagulation involves the addition of a quantity of a multivalent metal salt, preferably a bivalent or trivalent metal salt. For example, the multivalent metal salt may be a bivalent metal salt.
The multivalent metal salt may for example be a salt of beryllium, magnesium, calcium, strontium, barium, radium, aluminium or zinc. Preferably, the multivalent metal salt is a salt of magnesium, aluminium, zinc, or calcium. More preferably, the multivalent metal salt is a calcium salt.
The multivalent metal salt is a metal halogenide, for example a metal chloride.
The multivalent metal salt may for example be a salt of an alkaline earth metal.
For example, the multivalent metal salt may be selected magnesium chloride, calcium chloride, aluminium chloride, zinc chloride. Preferably, the multivalent metal salt is calcium chloride.
A quantity of for example 0.5 - 2.5 wt%, preferably 1.0 - 2.0 wt%, of the multivalent metal salt may be added for coagulation to the aqueous latex, with regard to the total weight of the aqueous latex.
Preferably, a quantity of 0.5 - 2.5 wt%, preferably 1.0 - 2.0 wt%, of the multivalent metal salt is added for coagulation to the aqueous latex, with regard to the total weight of the aqueous latex, wherein the multivalent metal salt is calcium chloride.
Also disclosed herein is a process for the production of a core-shell graft copolymer comprising coagulation of an aqueous latex comprising a quantity of particles of the copolymer and a quantity of a fatty acid surfactant, wherein the coagulation involves the addition of 0.5-2.5 wt% of a multivalent metal salt with regard to the weight of the core-shell copolymer particles present in the latex.
In this process, the metal may for example be selected from beryllium, magnesium, calcium, strontium, barium, radium, aluminium and zinc, and is preferably magnesium, aluminium, zinc and calcium; and/or the salt is a halogenide, preferably a chloride.
Further disclosed herein are articles comprising a surface area comprising a core-shell graft copolymer. In particular, the invention relates to articles wherein said surface area is coated with a metallic coating. For example, such metallic coating may be applied via electroplating. In certain preferred embodiments the metallic coating is selected from copper, nickel, gold, silver, platinum, or alloys thereof.
A core-shell graft copolymer can be produced by coagulation of an aqueous latex comprising a quantity of particles of the copolymer and a quantity of a surfactant, wherein the coagulation involves the addition of a quantity of a multivalent metal salt, preferably a bivalent or trivalent metal salt, wherein the core-shell graft copolymer comprises a quantity of elastomeric core particles onto which a fraction of thermoplastic polymer chains is covalently bound, and a quantity of thermoplastic polymer chains that are not covalently bound to the elastomeric core particles, wherein the elastomeric core particles are polybutadiene particles, and the thermoplastic polymer chains are poly(styrene-acrylonitrile) chains.
A core-shell graft copolymer can be produced by coagulation of an aqueous latex comprising a quantity of particles of the copolymer and a quantity of a surfactant, wherein the coagulation involves the addition of a quantity of a multivalent metal salt, wherein the multivalent metal salt is calcium chloride, wherein the core-shell graft copolymer comprises a quantity of elastomeric core particles onto which a fraction of thermoplastic polymer chains is covalently bound, and a quantity of thermoplastic polymer chains that are not covalently bound to the elastomeric core particles, wherein the elastomeric core particles are polybutadiene particles, and the thermoplastic polymer chains are poly(styrene-acrylonitrile) chains.
A core-shell graft copolymer can be produced by coagulation of an aqueous latex comprising a quantity of particles of the copolymer and a quantity of a surfactant, the surfactant being a fatty acid or salt thereof or a mixture of fatty acids or salts thereof, wherein the coagulation involves the addition of a quantity of a multivalent metal salt, wherein the multivalent metal salt is calcium chloride, wherein the core-shell graft copolymer comprises a quantity of elastomeric core particles onto which a fraction of thermoplastic polymer chains is covalently bound, and a quantity of thermoplastic polymer chains that are not covalently bound to the elastomeric core particles, wherein the elastomeric core particles are polybutadiene particles, and the thermoplastic polymer chains are poly(styrene-acrylonitrile) chains.
A core-shell graft copolymer can be produced by coagulation of an aqueous latex comprising a quantity of particles of the copolymer and a quantity of a surfactant, the surfactant being a fatty acid or salt thereof or a mixture of fatty acids or salts thereof, wherein the coagulation involves the addition of a quantity of a multivalent metal salt, wherein the multivalent metal salt is calcium chloride, wherein the core-shell graft copolymer comprises a quantity of elastomeric core particles onto which a fraction of thermoplastic polymer chains is covalently bound, and a quantity of thermoplastic polymer chains that are not covalently bound to the elastomeric core particles, wherein the elastomeric core particles are polybutadiene particles, and the thermoplastic polymer chains are poly(styrene-acrylonitrile) chains, and wherein multivalent metal salt is added to the aqueous latex in a quantity of 0.5-2.5 wt% with regard to the total weight of the core-shell graft copolymer particles present in the latex.
A core-shell graft copolymer can be produced by coagulation of an aqueous latex comprising a quantity of particles of the copolymer and a quantity of a surfactant, the surfactant being a fatty acid or salt thereof or a mixture of fatty acids or salts thereof, wherein the coagulation involves the addition of a quantity of a multivalent metal salt, wherein the multivalent metal salt is calcium chloride, wherein the core-shell graft copolymer comprises a quantity of elastomeric core particles onto which a fraction of thermoplastic polymer chains is covalently bound, and a quantity of thermoplastic polymer chains that are not covalently bound to the elastomeric core particles, wherein the elastomeric core particles are polybutadiene particles, and the thermoplastic polymer chains are poly(styrene-acrylonitrile) chains, wherein multivalent metal salt is added to the aqueous latex in a quantity of 0.5-2.5 wt% with regard to the total weight of the core-shell graft copolymer particles present in the latex, wherein the copolymer particles in the aqueous latex have an average particle diameter D₅₀ of ≥ 0.02 µm and ≤ 3.00 µm.
A core-shell graft copolymer can be produced by coagulation of an aqueous latex comprising a quantity of particles of the copolymer and a quantity of a surfactant, the surfactant being a fatty acid or salt thereof or a mixture of fatty acids or salts thereof, wherein the coagulation involves the addition of a quantity of a multivalent metal salt, wherein the multivalent metal salt is calcium chloride, wherein the core-shell graft copolymer comprises a quantity of elastomeric core particles onto which a fraction of thermoplastic polymer chains is covalently bound, and a quantity of thermoplastic polymer chains that are not covalently bound to the elastomeric core particles, wherein the elastomeric core particles are polybutadiene particles, and the thermoplastic polymer chains are poly(styrene-acrylonitrile) chains, wherein multivalent metal salt is added to the aqueous latex in a quantity of 0.5-2.5 wt% with regard to the total weight of the core-shell graft copolymer particles present in the latex, wherein the copolymer particles in the aqueous latex have an average particle diameter D₅₀ of ≥ 0.02 µm and ≤ 3.00 µm,wherein the fatty acid comprises ≥ 14 and ≤ 20 carbon atoms, and comprises ≤ 5 unsaturations.
The invention will now be illustrated by the following non-limiting examples.

Coagulation of polymer latex

An aqueous latex comprising a quantity of an acrylonitrile-butadiene-styrene (ABS) graft copolymer was subjected to a series of coagulation experiments. The ABS latex was obtained from an emulsion polymerisation process. The latex comprised 40.0 wt% solid matter, the solid matter consisting of 97.7 wt% ABS, and 2.3 wt% tallow fatty acid potassium salt, with regard to the total weight of the solid matter. The ABS comprised 32.1 wt% of polybutadiene, 45.6 wt% of moieties derived from styrene, and 22.3 wt% of moieties derived from acrylonitrile, with regard to the total weight of the ABS copolymer. The average particle size of the ABS copolymer in the latex was in the range of 0.05-0.50 µm.
In each of Experiments 1-4, a quantity of 42 liters (l) of the latex was added gradually over a period of 30 minutes (min) to a batch coagulator vessel containing 50 1 of water under stirring, where the vessel was subjected to heating such that after 6 min the temperature reached 79°C, after 12 min the temperature reached 82°C, and after 30 min, so when addition of the latex was completed, the temperature reached 85°C. The temperature was further increased to 90°C. At that point a quantity of coagulant was added as per Table I below:

Table I: Coagulant formulations

Experiment 1 (C) 2 3 4

Coagulant H₂SO₄ CaCl₂ CaCl₂ CaCl₂

Quantity of coagulant 1.5 1.0 2.0 3.0
The H₂SO₄ used in the Experiment 1 was 98% H₂SO₄. The quantity of coagulant is presented as parts by weight per 100 parts by weight of solid matter in the latex.
The mixture was maintained at 90°C for 10 minutes under stirring, after which a quantity of 150 1 water was added to the vessel to cool down the contents of the vessel to below 38°C.
Then, the coagulator vessel contents were transferred to a centrifuge and centrifuged to remove the water so that a wet cake having a moisture content of circa (ca.) 50 wt% was obtained. The wet cake was collected and fed back to the empty coagulator vessel together with 75 l of water of 50°C. After 10 minutes, another 125 1 of water were added of such temperature to cool the contents of the vessel to below contents of the vessel to below 38°C. The coagulator vessel contents were transferred to the centrifuge and centrifuged for 10 minutes to obtain a wet cake having a moisture content of ca. 35 wt%. The obtained wet cake was subjected to air drying at a temperature of 71°C until it contained ≤ 0.2 wt% of moisture. ABS Samples 1 through 4 were so obtained.
The obtained ABS samples were melt compounded with additives in a 7-zone 30 mm twin-screw melt extruder according to the formulations in Table II:

Table II: Compounding formulations

Sample 1 (C) 2 3 4

ABS 100.0 100.0 100.0 100.0

MgO 0.25 - - -

EBS wax 0.50 0.50 0.50 0.50

PEE 0.50 0.50 0.50 0.50

Phosphite 0.50 0.50 0.50 0.50

Wherein:

MgO is magnesium oxide, to neutralize the sulphuric acid, CAS reg. nr. 1309-48-4;
EBS wax is ethylene-bis-stearamide wax, CAS reg. nr. 110-30-5;
PEE is polyoxyethylene ether having Mw or 8800, CAS reg. nr. 9003-11-6; and
Phosphite is Ultranox 626, bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite, CAS reg. nr. 4122-20-3.

The melt extruder was operated at a speed of 250 revolutions per minute (rpm). The temperature settings of the melt extruder for each of the four exemplary grades are indicated in Table III:

Table III: Compounding extruder settings

Zone 1 2 3 4 5 6 7

Temperature (°C) 180 200 210 220 220 230 230
The product obtained from the compounding extruder was solidified and cut to pellets. From the pellets of each of Samples 1-4, films were produced using a 2.5 centimeter (cm) Sterling sheet extruder operated under the conditions as set out in Table IV:

Table IV: Film extruder settings

Zone 1 2 3 4 Die

Temperature (°C) 227 238 154 249 249

Screw speed 20 rpm Pressure 203 kPa

Roll speed 2.3 m/min Roll temp 82°C
For each of Samples 1-4, films were obtained of 11.4 cm width, 75 µm thickness, and 53 meter (m) length.

Determination of film properties

The films produced from the copolymer Samples 1-4 were tested to detect the quantity of gels. In this context, gels are to be understood as areas of undispersed materials protruding from the surface of the film for more than 20 µm. The determination of the gel content was performed using a sheet profilometer equipped with five 1.27 cm wide linear variable displacement transducer sensors. The sample films were conveyed along the sensors at a constant speed of 2.44 centimeter per second (cm/s). The gels were recorded as peaks recorded by the displacement sensors. For each sample, the quantity of peaks, and thus the quantity of gels, was counted for a 10-minute test run, equalling a length of 14.6 m of film length.
Further, the quantity of residual calcium in the films were determined in accordance with ASTM D7876 (2013). The results are in Table V.

Table V

Sample 1 (C) 2 3 4

Gel count 379 180 92 78

Residual Ca 0 1430 1440 1560
The objective to reduce gels is achieved by each of the Samples 2-4, in which the coagulant was a multivalent metal salt, over sample 1, wherein the coagulant was an acid that was subsequently neutralized during the compounding with a metal oxide MgO. Films of Samples 2 and 3 demonstrate a particular desirable balance of low gel count at low metal salt quantities added, which is desirable since this positively impacts process economics as well as residual metal content in the copolymer material. The presence of a low residual metal content is desirable as a too high content is understood to attribute to the occurrence of surface defects.
The terms "a" and "an" and "the" do not denote a limitation of quantity, and are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. "Or" means "and/or" unless clearly indicated otherwise by context. Unless defined otherwise, technical and scientific terms used herein have the same meaning as is commonly understood by one of skill in the art to which this invention belongs. A "combination" is inclusive of blends, mixtures, alloys, reaction products, and the like. "One or more of the foregoing" means at least one of the listed material. All amounts total 100 wt%. All ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other. In general, the disclosure may alternately comprise, consist of, or consist essentially of, any appropriate components herein disclosed. The disclosure may additionally, or alternatively, be formulated so as to be devoid, or substantially free, of any components, materials, ingredients, adjuvants or species used in the prior art compositions or that are otherwise not necessary to the achievement of the function and/or objectives of the present disclosure.
Unless specified to the contrary herein, all test standards are the most recent standard in effect as of the filing date of this application, or, if priority is claimed, the filing date of the earliest priority application in which the test standard.

Claims

An article comprising a surface area comprising a core-shell graft copolymer,
wherein the core-shell graft copolymer is a core-shell acrylonitrile-butadiene-styrene graft copolymer produced by coagulation of an aqueous latex comprising ≥ 10.0 wt% and <40 wt% of the copolymer and a quantity of a surfactant, wherein the coagulation involves the addition of a quantity of a multivalent metal salt, preferably a bivalent or trivalent metal salt, or a lithium salt, wherein the salt is a halogenide,

wherein the surface area comprising the core-shell graft copolymer is coated with a metallic coating.
Article according to claim 1, wherein the whole surface area is coated with the metallic coating.
Article according to any one of claims 1-2, wherein the metallic coating is applied to the article by means of electroplating.
Article according o any one of claims 1-3, wherein the metallic coating comprises at least one selected from copper, nickel, gold, silver, platinum, or alloys thereof.
Article according to any one of claims 1-4, wherein the salt is a chloride.
Article according to any one of claims 1-5, wherein the surfactant is a fatty acid or a salt thereof, or a mixture of fatty acids or salts thereof.
Article according to any one of claims 1-6, wherein the metal comprises at least one selected from beryllium, magnesium, calcium, strontium, barium, radium, aluminium, or zinc; preferably at least one selected from magnesium, aluminium, zinc, or calcium.
Article according to any one of claims 1-7, wherein the multivalent metal salt or lithium salt is selected from at least one of magnesium chloride, calcium chloride, aluminium chloride, zinc chloride, or lithium chloride.
Article according to any one of claims 1-8, wherein the multivalent metal salt is added to the latex for coagulation in a quantity of 0.5-2.5 wt% with regard to the weight of the core-shell graft copolymer particles present in the latex.
Article according to any one of claims 1-9, wherein the coagulation of the aqueous latex is free of magnesium oxide.
Article according to any one of claims 1-10, wherein the elastomeric core particles are trimodal, wherein the particle size distribution is determined in accordance with ISO 9276-2 (2014), preferably, wherein the elastomeric core particles have a first peak at < 200 nm, a second peak at 200 - 500 nm, and a third peak at > 800 nm.